Introduction To Java Programming

Java is a powerful, object-oriented programming language developed by James Gosling at Sun Microsystems in 1995. Java is known for its platform independence, security, portability, and robustness, making it one of the most popular programming languages in the world.

• Java syntax is simple, structured, and object-oriented.
• Every Java program starts from a class and main() method.
• Every statement ends with a semicolon ( ; ).
• Code blocks are grouped inside curly braces { }.

class Main
{
    public static void main(String args[])
    {
        System.out.println("Hello, PBA INSTITUTE");
    }
}

class Main
{
    public static void main(String args[])
    {
        int a=2, b=3, c=5, l=6, e;

        e = a + b + c + l;

        System.out.println("sum = " + e);
    }
}

class Main
{
    public static void main(String args[])
    {
        int a = 6, b;

        b = a * a;

        System.out.println("Area of square = " + b);
    }
}

• Java programs always begin execution from the main() method.
• Every statement in Java ends with a semicolon ;.
• Java is case-sensitive. Main and main are different.
• Always use meaningful variable names for better readability.
• Practice small programs daily to improve programming logic.

• Q1. Write a Java program to print your name.
• Q2. Write a Java program to add two numbers.
• Q3. Write a Java program to calculate the area of a rectangle.
• Q4. Write a Java program to swap two numbers.
• Q5. Write a Java program to print Hello World.

• Forgetting semicolons at the end of statements.
• Using incorrect class names.
• Writing code outside the main() method.
• Ignoring Java naming conventions.
• Not compiling before execution.